Tutorial 3 Part 1

Fear and loathing in PhotoImpact

Unraveling the mysteries of Channels, Tone Maps, and Calculations

If you have ever encountered this somewhat daunting box, either by accident or choosing Calculations from the Format Menu, you might have wondered, “What in the world can this thing possibly do for me?” Well, believe it or not, a similar dialog is available in Adobe Photoshop and 90% of the users of that program hit the Cancel button immediately. One can get away with that in Photoshop, because there are other options, such as the Channels Palette, that enable access to manipulation of the separate Red, Green, and Blue channels that make up a digital image. If you are using PhotoImpact, you have no choice but to use the ToneMap and Calculations. And Ulead, in its not always sensible but always well-meaning manner, has chosen to mention each of these powerful tools in one sentence in the User Guide. The Online help isn’t much better.

If you really need to do color correction (and most of us with scanners really do); or if you need to make a serious and complex mask; or if you would like to do some composite editing (pasting and masking several pictures together), these are the tools you need. And they are available to you at about $500 less than Photoshop! So let’s get with it.

Please note that I am assuming some prior knowledge of PhotoImpact fundamentals on your part. If you’re not sure about selection tools, masks, objects and such, spend some time with your User Guide. Or better yet, visit Stephanie’s Tutorial Pages for some real info. And also let me say that this is not intended to be a master class on RGB channels. If you really want to know how a digital image is processed from file to screen, go to your local library and check out any decent Photoshop guide. For these tutorials you only need to know the channels are there and how you can use them. So let’s again take a look at that Calculations dialog box.

For many people, this box is at first confusing because of its horizontal structure. If you think of it as a Layers Manager on its side, it makes more sense. The red type describes each of these components seen as layers or objects. The image at the far right of the dialog is the final image produced after clicking OK. The pull-down menu called Operation is nothing more than various Merge modes you see in Object Properties. The main difference in Calculations is that you are masking and merging full images (and sometimes channels) instead of objects. The pixel dimensions are marked in red because every image to be used in this dialog box must be exactly the same size, not one pixel different.

Open the downloaded file called Arches. Then choose Calculations from the Format menu and we’ll begin to look at channels. Since we only have one image open, at the present time this is the only one available to us in the box. Click on the Channel drop down menu and you will see options for choosing the Red, Green, or Blue channels or the composite of all three, called Master. As an initial experiment we’re going to replace the sky in this picture with a more interesting sky, so I’ll show you how easy it is to make mask from this box.

Under the Foreground image click on the Channel drop-down menu and choose Red. Don’t click OK yet. What we’re looking for here is the highest contrast channel of the three. Then look at the Green channel and finally the Blue. Obviously, in this case the Blue channel gives us the best contrast to work with. So click on Blue, be sure the Background image is Master, and click OK. Presto, your Blue channel information is now an image in PhotoImpact. It’s useful to rename this document, so choose File>Save As (Ctrl+Shft+S) and name it “Mask.”

If you now reopen your Calculations box and click on the first of the drop-down menus, you’ll see that you now have two choices in both the Foreground and Background sections. We have to make our mask next, so cancel out of the dialog. Make sure you have your Mask image selected and choose ToneMap from the Format menu. With this Blue channel we can really crank up the contrast in a way we couldn’t with our original photo. Click the Highlight Midtone Shadow tab and enter 30 for the Highlight and -100 for the Shadow. These setting are naturally different for every image and just happen to work well with this one. You should now have a black and white image like the one below. And here’s where the magic begins.

Open the Star Scene photo from your download files, and once again open your Calculations dialog. The foreground image should be Star Scene Master. Check the Mask box. Choose Mask from the drop-down menu underneath, and keep the channel at Gray. In the Background image menu choose Arches and Master. Click OK. You now have a fourth image open which is a composite of the previous three. And it shouldn’t look too bad for the short amount of time it took to make.

But notice the blue “fringing” around the arches that makes it pretty obvious the photos came from different sources. Let’s take a few more minutes to make it look right. Close that new image without saving. We’re going to use a few tricks any image editor worth his billable hours uses all the time.

As you probably know, a mask works by letting an image show through completely where it is white, not at all where it is black, and in 254 varying degrees of transparency where it is gray. Select your Mask Image. If we expand the white area around the arch and then soften it a bit, we’ll get rid of most that fringing. Choose the Magic Wand tool, set the Similarity to 5, and from the Options drop-down choose Compare By HSB. Click your Magic Wand on the black area. Then from the Selection menu choose Invert and all the white pixels will be selected.

When you’re finished, at the Selection menu click on Expand/Shrink. Click the Expand radio button and enter 2 pixels, then click Circle in the Shape option. OK. Open the Fill dialog box (Ctrl+F). Select white and click OK. From the Selection menu choose None to get rid of the marching ants. Now choose Blur and Sharpen from the Effects menu and click on Average. A Square size of about 5 should soften the edges the way we want, so enter 5 and click OK. Now set up your Calculations dialog box exactly as it was: Star Scene in Foreground, Mask in the center, Arches in Background. Click OK.

Not bad, huh? If this were going to print, it would need still more work, but since your just getting your feet wet, admire your handiwork for a while and close all. Save the picture if you want. If you enjoyed this tutorial, I hope you will return for Parts 2 and 3. We’ve only scratched the surface of the power of Channels and Calculations. In Part 2 we’ll really get our hands dirty with color correction using the Red, Green, and Blue channels in the ToneMap dialog. And in Part 3, we’ll expand on Calculations and digital compositing. At the very least, I hope you no longer fear and loathe the Calculation dialog box.

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